Apo-Eε4 allele in conjunction with Aβ42 and tau in CSF: biomarker for Alzheimer's disease.

The objective of this study was to elucidate an association between Apo- Eε4 allele and CSF biomarkers Aβ42 and tau for the diagnosis of Alzheimer's Disease (AD) patients. Aβ42 and tau protein concentrations in CSF were measured by using ELISA assays. The levels of Aβ42 were found to be decreased where as tau levels increased in AD patients. Moreover in AD patients Apo-Eε4 allele carriers have shown low Aβ42 levels (328.86 ± 99.0 pg/ml) compared to Apo-Eε4 allele non-carriers (367.52 ± 5 7.37 pg/ml), while tau levels were higher in Apo-Eε4 allele carriers (511 ± 44.67 pg/ml) compared to Apo-Eε4 allele non-carriers (503.75 ± 41.08 pg/ml). Combination of Aβ42 and tau resulted in sensitivity of 75.38% and specificity of 94.82% and diagnostic accuracy of 84.30% for AD compared with the controls. Therefore low Aβ42 and elevated tau concentrations in CSF may prove to be a better diagnostic marker for AD along with the Apo-Eε4 allele.